Editing Trigger finger


''(Stenosing flexor tenosynovitis)''

== '''Epidemiology''' ==

* Most common in women 40-60yo
* Higher prevalence in diabetics, arthritis, and amyloidosis

== '''Aetiology''' ==

* Unknown
* Often attributed by patients to overuse or repetitive movements
* When seen in children, higher prevalence of anatomic variations or inherited conditions

== '''Pathophysiology''' ==

* A disparity in size of the flexor tendons and the surrounding retinacular pulley system at the A1 pulley. The flexor tendon catches when it attempts to glide through a relatively stenotic sheath.
* Results in difficulty smoothly flexing or extending the finger, and sometimes even locking, in severe cases.
* The histopathological change is fibrocartilaginous metaplasia of the ligamentous layer of the tendon sheath at the A1 pulley, with reduction in the cross-sectional area of the fibro-osseous canal.
* Not unusual to have multiple trigger fingers
* A1 pulley is overlying MCPJ (see below)





== '''Diagnosis''' ==

* Locking at MCPJ
* Palms up, and trial active extension and flexion to elicit locking
* Palpate over PIPJ as the finger is actively flexed and extended, to assess for clicking/catching
* The locking does not have to occur with every movement
* Locking indicates more severe disease
* XR is unnecessary in most cases

== '''Differential diagnosis''' ==

* Dupuytren's contracture (fixed and chronic loss of full extension, at the MCPJ; painless, with nodules usually palpable in the palmar fascia)
* Diabetic cheiroarthropathy (typically affects all fingers symmetrically)
* MCPJ sprain (recent trauma)
* Infection
* RA - a snapping phenomenon can occur with flexor tendon synovial inflammation at the carpal tunnel

== '''Indications for surgery''' ==

* Failed conservative management (activity modification, splinting in slight flexion, short-term NSAIDs)
* Not appropriate or unwilling to try one or two glucocorticoid injections
* Secondary trigger finger (to other medical condition) which is unlikely to resolve with surgical management

== '''Contraindications''' ==

* RA - these patients should have open synovectomy and excision of intra-tendinous nodules, leaving the A1 pulley intact

== '''Surgery''' ==

* '''Technique - finger'''
** Wide awake, LA, no tourniquet
** Can be transverse, longitudinal or chevron incision over the A1 pulley
**
** Use Metz scissors to expose the tendon sheath with gentle spreading. Blunt ends of cats paw retractors to protect other structures/expose.
**
** Take the finger through several cycles of active movement to ensure full release
** Close the wound (4/0 Nylon or Vicryl Rapide)
** Rehabilitation is unnecessary, unless contractures were present, but encourage finger ROM
* '''Technique - thumb'''
** Beware of radial digital nerve of the thumb - crosses obliquely over the A1 pulley, especially proximally
* '''Complications'''
** Recurrence 3%
** Infection
** Digital nerve injury
** Flexor tendon bowstringing

[[Category:Skin, soft tissue and wounds]]